The Madison Police Department is investigating a homicide after a man was found dead in his downtown apartment.

The victim, a man in his 40s, was found by his female roommate in their 27 N. Butler St. residence Monday evening, MPD Chief Mike Koval told the Wisconsin State Journal.

MPD’s Violent Crime Unit is leading the investigation, according to an MPD incident report. Investigators said evidence led them to conclude the death occurred under “suspicious circumstances.”

The MPD Central District detectives, Forensic Unit investigators, crime analysts, and Criminal Intelligence Section officers are also cooperating in the investigation, according to MPD Public Information Officer Joel DeSpain.

He said no suspects are being ruled out, but it does not seem as though the roommate who discovered the body was involved. He could not discuss specifics of the investigation, but said the teams are following many leads.

“It would be protocol for investigators to pursue many paths: canvass the neighborhood; talk with the victims’ contacts, family and friends; try to retrace the victim’s last few days; look for any surveillance video that might be beneficial; take any forensic evidence to the Wisconsin State Crime Laboratory,” DeSpain said in an email.

The exact time and cause of death are unknown. DeSpain said MPD investigators are “firming up a timeframe with assistance from the Dane County Medical Examiner.”

UPDATE March 28, 2:38 p.m.: This story was updated to include further information from the Madison Police Department Public Information Officer.